Two new species of African Haemaphysalis ticks (Acari: Ixodidae), carnivore parasites of the H. (Rhipistoma) leachi group.

Two new tick species belonging to the African Haemaphysalis (Rhipistoma) leachi subgroup, namely H. (R.) colesbergensis n. sp. and H. (R.) oliveri n. sp., are described. Haemaphysalis (R.) colesbergensis adults are easily differentiated from the other species of the H. (R.) leachi subgroup, including H. (R.) oliveri, by the spur on coxa IV, which is considerably longer than that on coxa III. The adults of the 2 new species are equal in size, but the dental formula of the hypostome of H. (R.) colesbergensis is 4/4 compared to 5/5 for H. (R.) oliveri. The dental formula of H. (R.) oliveri also distinguishes it from other ticks in the subgroup, namely H. (R.) leachi, H. (R.) elliptica, H. (R.) moreli, and H. (R.) punctaleachi (4/4 in these species), but not from H. (R.) paraleachi, which has a 5/5 dental arrangement. However, the average total length and width of H. (R.) oliveri males (2.47 x 1.20 mm) are considerably shorter and narrower than those of H. (R.) paraleachi males (3.81 x 1.79 mm). Similar differences in size apply to the females. Nymphs and larvae of H. (R.) colesbergensis and H. (R.) oliveri can be distinguished from those of other members of the H. (R.) leachi subgroup, as well as from each other, by a combination of the following characters: size and measurement ratios, length of posterodorsal and posteroventral spurs on palpal segment II, and number of denticles per file on the hypostome. Haemaphysalis (R.) colesbergensis is known only from South Africa, where it has been collected from domestic cats and dogs and medium-sized wild felids. Haemaphysalis (R.) oliveri is recorded only from Sudan, where it has been collected from small- to medium-sized wild felids and canids and an antelope. The hosts of the immature stages of H. (R.) colesbergensis are unknown, while nymphs of H. (R.) oliveri have been collected from rodents.